Valve for rock drills



Dec. 2, 1930.

J. c cuRTls f VALVE FOR ROCK DRILLS Filed Feb. 19, 1930 T Y U Qlfj 122%'fr ,n

INVENTOR.

Hfs ATTORNEY.

f UNITED STATES JOHN c. CURTIS, or EASTON, PENNSYLVANIA, AssIGNoEroINarnasoL'L#RAND coiii- Patented ec.v 2',

PANY, or JERSEY Merry, NEW JERSEY, A coRPoEATroNoE NEW lJERSEY vALvE EonRocx DRILLS f Application med- February/"19,rieaopseriai No. 429,554. i

This invention relates to 4rockdrillsybut more particularly to adistributingvalvefor rock drills of the fluid actuated type.

AThe objects of the invention are to obtain i: 5 a rapid and positiveaction of thevalve, toas-Y sure a heavy' blow against ,thel working implement, and to minimize the volume .of pressure fluid consumption foractuating the tool.

Y Other objects will be in part obvious and I510 in part pointed outhereinafter.

In the accompanying drawings forming part of this specification and inwhich similar reference characters refer to similar parts, Y.

Figure l is asectional elevation of a rock lT115 drill equipped with avalve constructed in accordance with the practice ofthe invention, thevalve being shown in posi'tion tosupply pressure fluid to-the rear endof the piston chamber, and f v3120 Figure 2 is asimilar view showing thevalveV in a position for supplying Vpressure fluid to the "front end ofthe piston chamber.

Referring to the drawings, the vinvention is `shown embodied ina rockdrill A comprising "125 a cylinder B having a piston chamber ,C to

receive. Va reciprocatory vhammer piston Y D, The cylinder B Visprovided with' an exhaust port E intermediate itsyends andthe exhaustport E is inthis instance controlled V bythe pistonl),A

Disposed at the front end oflthefcylinder B is a frontcylinderwasher'Fto form a closure for that end of the piston chamber C and to centralizea front head G with respect to 253-5 the cylinder B. An additionalfunction of the front cylinder washerA F is to act asa guide for an'anvil block H which is disposed slidablyinthe front cylinder washer FL?The anvil block extends into the front en'd of the o piston chamber C totransmit the blows lof the Y hammer pistoni) to a'worli-ng amplement J esuitably guided Vby the front which may be head Gr.v v l In the rear endof the cylinder B is a bore K to receive a valve chest'L which inthis-instance comprises V,outerv and inner members OA and P, The'routermember O is inthe-form of a ring and is provided with a suitable'bore-Q,

for'the accommodation of the inner 'member 5D P, lThe members O and Pmay beseated uponV vbe lsecured to the cylinder B a plate which isdisposed adjacent rear l end of the piston chamber C to forma closuretherefor. ,i

head S which may formthe rearmost part of the casing A and-like thefront head G, may by means of sidebolts (not shown). i -Y lhe back headS servies as a throttlevalveT which maybe ofthe rotary type and has acentral chamber U into which Seated upon themembers O and'P is housingfor a i pressurefiuid maybe constantly introduced p from asource ofsupply. 'i v v In the `wall of the throttle lvalve-Tis a port V toregisterwith a supplypassage W in the back headvSin the members O and Pand opening with its outlet end into a valve'chamber X'ufo'rmed inthisinstance in the member P to accommodate a distributing valve Y.

VThe valve chamber X comprisesan enlarged portion Z which constitutesthe"l front end of the, valvechamber and a reduced rearward l portionbintowhich extends a stem 0V of the valveY;V n y n l The, outletopeningfof the Supplypassage W preferably opens into the enlargedvportion Z of the valve chamberX atapoint approxifmatelyvmidway betweentheqends-of the enlarged portionZ. Inthe'plateRand prefer`v 1 .ablyarranged coaxially with thevalve `chamber X' is a rear inlet passagedthrough which pressure fluidV may -flow .into the rearend of the pistonchamber to actuate thepiston D forwardly. I

The pressure-fluid supplied to the front S5 `endyof the Apiston chamberCfor actuating Y `"the pistonD rearwardlyis conveyed thereto` by a frontinlet passage ein thewall ofthe portiorifb.l l e, i ,Y In order tolighten` the `valve Y, said -valve YcylinderB, the plate R, theVmembers@ and P -Vand opens into thevalve chamber at the j uncture ofthe'enlarg'ed portionZ andthe reduced y may be provided with a recessvwhich in this f instanceV opens from the i frontl end of the fvalvegY,thus leaving af wall gat the rear end of the stem 0.aV Nearthevfront end ofthe valve Y are a pair of iangeshfand j' forming l '-'aspacezlc therebetween .which is inV constant vcommunication with. theSupply passage `,100

The flange L may be termed the front flange and is provided with aplurality of ports o through which pressure fluid flows from the space7c into the front end of the enlarged portion Z of thevalve chamber forsupplying the rear end of the piston chamber C. Similarly, the flange isprovided with a series of ports p through which pressure lluid flowsfrom the space c to the inlet passage e for supplying the front end ofthey piston chamber C.

The ports p may, as illustrated, be of smaller area than the ports 0 sothat a lesser amount of pressure fluid'will Vbe supplied within a giventime to the front end of the piston chamber for actuating the piston Drearwardly than is supplied to the rear end of the piston chamber foractuating the piston D on its working stroke. This is desirableinasmuchthat it enables the piston D to be moved rearwardly at a speedcommensurate with the best efficiency of the drill, and at the sainetime it permits reversal of the piston at the end of its return strokewithout causing excessive jars or shocks to the drilling mechanism.

The front end of the flange L constitutes a pressure area g againstwhich pressure fluid may act tending to throw the valve Y rearwardly,and on the rear end of the flange 7' is a pressure area 1'- aga-instwhich the pressure fluid flowing through the ports p may act forthrowing the valve Y forwardly. The pressure aiea i is of smaller areathan the pressure area g.

Adjacent the pressure area r is a stepped portion s, the rear surface ofwhich constitutes an actuating surface t which is intermittently exposedto compression flowing from the front end of the piston chamber C toassist the pressure fluid acting against the pressure area-41 foractuating the valve Y.

Additional means are provided for actuating theIvalve Y from one end ofthe valve chamber to the other. To this end the front end of the wall gserves as an actuating surface u against which compression from the rearend of the piston chamber may act to assist in throwing the valve Yrearwardly. The opposite side or rear end of the wall g likewiseconstitutes an actuating surface o which is intermittently exposed topressure 'fluid to assist the pressure fluid acting against the surfacesfr and t for throwing the valve Y forwardly. The pressure fluid thusacting against the actuating surface o isconveyed to the rear end. ofthe reduced portion b of thevalve chamber by a kicker passage w whichcommunicates with its inlet opening or port c with the rear portion ofthe piston chamber C and preferably at a point closely adjacent theexhaust port E.

The reduced portion Zi of the valve chamber X is provided with anexhaust passage y which opens to the atmosphere andis so located that itwill be uncovered by the rear' end of the valve when the valveapproaches the front end of the valve chamber.

The operation of the device is as follows: VVith the valve in therearmost position illustrated in Figure l, pressure fluid will flowthrough the ports o into and through the front end of the valve chamberX, thence through the rear inlet passage cl into the back end'of thepiston chamber to drive the piston D forwardly.

During the admission of pressure fluid into therear end of the pistonchamber pressure fluid will also pass through the ports p to act againstthe actuating surface r. Such pressure fluid acting against theactuating surface r however, will be ineffective to change the positionof the valve Y as the valve is exposed to pressure fluid over itsforwardly 'facing surfaces, such as the pressure area g and theactuating surface u. The valve will therefore remain firmly seated inthe rear end of the valve chamber until the piston D uncoversthe port xof the kicker passage w. This will take place immediately before thepiston D uncovers the exhaust port E and pressure fluid will then flowthrough the kicker passage w into the rear end of the valve chamber toact against the actuating surface o.

Immediately upon the uncovering of the exhaust port E by the piston thepressure acting against the .forward surfaces of the .valve Y will dropconsiderably below line pressure. When this drop in pressure occurs thepressure or pressures acting against the surfaces o and r, together withthe compression whichrflows from the front end of the piston chamber Cto act against the actu ating surface t, will move the valve Y forwardlyto close the inlet passage c.

This movement of the valve Y may take place slightly prior to theinstantrof impact of the hammer piston D against the anvil block H sothat an immediate supply of pressure fluid Amay be introduced into thefront Yend of the piston chamber C to return the piston D. The pressurefluid serving to return the piston D flows from the space 7c between theflanges through the ports p and thence through the rear end of theenlarged portion of the valve chamber and the front inlet passage e tothe front end of the piston chamber C.

During the admission of pressure fluid to the front end of the pistonchamberthe valve Y will be momentarily held stationary in the front endof the valve chamber by the pressure fluid acting against the surfaces rand if. The pressurefluid previously admitted into the rear end of thereduced portion of the valve chamber may be exhausted therefrom throughboth the kicker passage w and through the exhaust port E, and alsothrough the exhaust passage y.

As the piston D moves rearwardly and after it covers the exhaust port Ethe air in the rear end of the piston chamber C will be compressed. Thiscompression will act against the actuating surface u and, together withthe pressure fluid acting against the actuating surface g, will move thevalve to its initial position for admitting pressure fluid into therearend of the piston chamber C.

I claim: y

l. In a fluid actuated rock drill, the combination of a cylinder havinga piston chamber and a hammer piston in the piston cham-` ber, anexhaust port in the cylinder, a valve chest having a` valve chamber,inlet passages leading from the valve chamber to the piston chamber, avalve in the valve chamber controlling the inlet passages, a pair offlanges on the valve having apertures therein through Y.

which pressure iiuid flows to the inlet passages, a supply passage inthe valve chest for introducing pressure into the valve chamber betweenthe flanges, pressure areas on the flanges against which the pressurefluid iiowing through the apertures acts for throwing the valve,opposed` actuating surfaces on the valve, one of said actuating surfacesbeing intermittently exposed to compression to assist in throwing thevalve in one direction, and a kicker passage leading from the cylinderto the valve chamberandcontrolled by the piston to expose the otheractuating surface to pressure fluid for assisting in throwing the valvein the opposite direction.

2. In a fluid actuated' rock drill, the combination of a cylinder havinga piston chainber and a hammer piston in the piston cham-V ber, anexhaust portin they cylinder, a valve chest having a valve chamber,inlet passages leading from the valve chamber to the piston Y chamber, avalve in the Vvalvechamber to control the inlet p assages, a' pair offlanges on the valve havingpressure areason'their outer Y ends, saidanges having ports for supplying pressure fluid to the pressure areasfor throwing the valve and for supplying pressure fluid to the inletpassages, a supply passage in the valve chest for supplying pressureHuid to the valve chamber between the flanges, opposed actuatingsurfaces on the valve, one of said actuatingV surfaces beingintermittently ex posed to compression to assist in throwing the valvefor admitting pressure fluidto'the rear end of the piston chamber, and akicker pas# l sage leading from the rear end of the piston chamberto thevalve chamber and controlled by the piston to expose the other actuatingsurface to pressure fluid to assist in throwing the valve for admittingpressure fluid to the front end of the piston chamber.

In testimony whereof Ihave signed this specification.

Joris o. smeris.

